Metamorphosis
by FinalDestinationLover45
Summary: Percy, Annabeth, Thalia, and Piper are on vacation in Australia. But, what'll happen when the girls come back with more than they bargain for? Story better than the summary, trust me.
1. Chapter 1

**Metamorphosis**

**an H2O & Percy Jackson crossover**

Author's Notes: I DON'T OWN H2O OR PERCY JACKSON.

_**Chapter 1- Departure **_  
**Annabeth's P.O.V **

Percy, Thalia, Piper, and I are finally going on a vacation! We're going to a place called Mako Island.

Too bad I have to talk to Chiron before we board the boat.

In Chiron's office 

I was waiting for Chiron to start talking about whatever he needed to talk about.

By the way, did I forget to mention that Chiron is a centaur? I didn't? Well, I'm mentioning it now.

"Hello, Annabeth. Now, here's my warning. Mako Island is a dangerous place. The locals say that strange things happen there during a full moon, which happens to be on the 4th day of your voyage. So, be careful."

I heard the indistinct sound of a ship's foghorn. Chiron then said, "I hear your boat approaching. And, if you have any business you need to take care of, I suggest you do it now. Hurry, _The Argo III_ awaits your entrance. "

There was some business I wanted to take care of: mending the relationship between me and my boyfriend, Percy.

**On the shore **

I was walking on the shore, when all of a sudden; two hands went over my eyes.

I unsheathed my dagger, and a voice behind me said, "What? You're going to try and kill me for trying to be funny? That's messed up, Annabeth."

Oh, my gods. My boyfriend is never going to leave me alone.

Ever since he got back from Camp Jupiter, he's been trying to make up for the lost time we had.

He also got a couple of mementos from the other camp: a Legion tattoo, and a whole new attitude.

"Sorry," I said. "But you know, when someone sneaks up behind me, I spring into action."

I was rewarded with a slight chuckle. "Now," Percy said, "are you sure you want to go?"

"Yeah." I said. Besides, when was the last time we had a vacation? I really can't remember.

**On the Argo III  
**  
Let me paint a mental picture of the boat for you. It basically looks like a fishing boat, except new and shiny, with a gorgon for the masthead, and a brand new motor. Next stop, Mako Island!

**Author's Notes:**There's going to be another chapter posted soon!


	2. Chapter 2

_**Chapter 2- Transformation **_  
**Piper's P.O.V **

**Author's Notes:**Since you liked the first chapter, I posted the next one. In fact, I think I might finish this story today. All flames about this story will be used to roast marshmallows.

I can't believe it! This is the first time I've ever been to Australia.

Well, technically, not Australia, just an island off the coast of there.

Anyways, I wish Jason was here to see this, and that he didn't have to go back to Camp Jupiter.

Stupid Reyna, I thought. Well, he's the camp praetor. He belongs there. Wait… I thought I just saw a fin come up out of the water.

So of course I unsheathed my dagger, Katoptris, out on instinct. And whatever had that fin was jumping out of the water, it was a girl. A mermaid!

I freaked out, and I really needed my friend's views on the situation. "Guys," I said, "is it just me, or did I see a mermaid come out of the water?"

Thalia looked like she was trying not to laugh, Annabeth had her thinking face on, so she was of no help, but Percy was staring intently at the water. I already knew what he was doing. He was checking the water for any sign of the mysterious mermaid.

He looked at me with a curious gaze, and said, "I can't seem to find anything, Piper. Are you sure you saw a mermaid, or a dolphin?"

I felt like slitting his throat with my dagger, so to calm down, I went to the bow of the boat.

And then I saw the mermaid again.

She had tan skin, brown eyes, and dark brunette hair, similar to mine.

She put her finger to her lips as if she's saying, 'This is our little secret.'

Then she dove back into the water.

Was I finally going crazy?

**Percy's P.O.V**

I can't believe Piper thought she saw a mermaid halfway to the island.

You know, sometimes I wonder about that girl. Wait, why am I concerned with Piper? We are on a vacation! Well, not really… Still, it gives us time to relax.

My nautical senses told me we were almost to the island, but I didn't see it because of a line of fog in our way. The only thing visible was the full moon hanging over our heads, which cast an eerie glow onto the ship. Thank you, Artemis for making this trip creepy now. I was being sarcastic, in case you didn't notice.

I walked around the boat, and I saw Annabeth standing on the bow of the boat staring out into the distance. So, I walked up to her, and said, "Hey, Annabeth. It's a full moon. We're alone on the bow of the ship." I glanced at Annabeth, and she had a thinking look on her face.

"Percy," she said. "Do you ever feel like you have to trust your instincts? Well, I'm trying to trust my instincts about you."

She needs to trust me?

"Do you remember that day at camp," she asked. "When I told you I had strong feelings for you, and I just had to decide whether they were positive or negative?"

That was the first time me and Annabeth actually talked. I mean, after she tried to freakin' kill me!

"Yeah?"

"Well," she said. "I've decided. And they definitely are-"

She was cut off by the sound of wood scraping against sand.

Now my nautical senses confirmed we have arrived at the mysterious Mako Island. The worst part about crashing the boat: It threw me forward and straight into Annabeth, knocking her over.

"You plan on making this worth my while?" Annabeth joked.

On the upper deck of the boat, I heard the indistinct sound of a conch horn over the sound of the blood rushing in my ears.

Then, I heard a voice yell, "All ashore that's going ashore! Final stop, Mako Island!"

Obviously, Thalia is going mental with a pirate themed trip.

Then she looked down at me and Annabeth on the deck and yelled, "If you two lovebirds are done making out, we have an island to explore!"

On the island  
This island reminds me of something out of an Indiana Jones movie, with all the plants. And, thanks to the fog, it added an element of mystery to the island, like you don't know what'll pop out of those woods.

In fact, it's so creepy; I thought I just heard a scream like right next to me. I looked over my shoulder to see Piper walking towards something in the ground.

At that moment, I heard Thalia yell, "All right, who the wise guy that dug this hole?"

A hole? In the middle of the jungle? I found that hard to believe, until I tripped and slid down a sand slide, and landed right on my face.

**Thalia's P.O.V**

I was so ticked off about whatever possessed someone to dig this hole; I didn't hear the sound of someone screaming. Then I heard the sound of someone groaning in pain.

I looked over my shoulder to see Percy lying on the ground, halfway near crying. I decided to play around with him, and I said, "You have a cushy landing?"

He snapped, "At least you didn't land on your face!" Then he clutched the side of his face in pain, and said through clenched teeth, "Ow. I think I broke a tooth."

I heard the sounds of two more people screaming. Great, time for Annabeth and Piper to join the party.

The good news about their landing: They made it down the hole in one piece.

The bad news: Annabeth landed on her ankle, and Piper looked like she could break her back. Wow, I didn't know the human body could bend that way.

"Could someone call a chiropractor?" Piper asked, amidst her pain.

"Wow," Annabeth said in awe. "I've never seen anything like this in my life."

I peeked over my shoulder to see a pool of water in the volcano, like nature's most secret Jacuzzi. "Hey," I said. "What if we jumped into that little pool right there?"

"I guess I could," Piper said.

"I'm up for it," Annabeth said, still looking around the cave.

"I don't want to," Percy said.

"That's okay," I said, "you don't have to if you don't want to." Piper, Annabeth, and I walked up to the edge of the pool. "Ready? One, two… THREE!"

We jumped into the pool together. For a moment, I saw nothing but a sheet of white bubbles across my line of vision, but my natural buoyancy brought me back up.

I looked over to find Annabeth hitting Piper's back, while Piper was coughing up water.

I looked up to see the moon, which was lining up with the mouth of the volcano, and it was unnaturally large tonight.

Then, the weirdest thing happened. The water started to bubble, like a giant soup pot, and it happened the moment the moon lined up with the mouth of the volcano. How weird.

"Uh," Piper said, with a hoarse voice from coughing up all that water. "I don't want to be in here anymore."

I looked up to find Percy just staring dumbfounded at the pool of water.

"You just going to stand there?" I asked. "HELP US!"

He held out his hand, and at that very moment, I felt a little seismic activity right on the seabed.

Next thing I knew, I was being propelled into the air out of the volcano by a jetstream of water along with Piper and Annabeth, and we landed right onto the boat.

I'm never going to Mako Island again!

**Back at camp**  
**Annabeth's P.O.V  
**  
It's been a week ever since we got back from Mako Island, but nothing strange has happened… yet.

Anyways, Percy and I are sitting on the shore of Long Island Sound, making up for the time lost on the boat when we crashed into the shore. Then, he did something that I never expected to do.

"Hey," he said. "Before we crashed into the shore, what were you saying about your feelings for me?"

"Well," I began, finding myself unable to stop talking. "I was going to say that my feelings for you are definitely positive and if you need to talk with me about anything, you're more than welcome-"

As if on instinct, he leaned forward and kissed me. Even though it didn't last very long, I felt like I was floating away.

"That was a really nice way of telling me to shut up," I said hazily.

I thought I felt someone behind me, but I got a clue of who it was when I felt a water balloon burst in the back of my head. I looked over my shoulder to find Connor and Travis Stoll rolling on the ground and laughing with a bucket of water balloons next to them.

Travis was about to launch another balloon, but Percy scared them away with his own personal hurricane.  
"Annabeth," he said. "Are you okay?"

Then I felt like I was dissolving.

I looked up to see Percy with a dumbfounded look on his face. Why was he looking at me like that?

Then I fell on my face. How embarrassing.

Until I looked down at my legs… or where my legs should have been. And were replaced with a glittering gold mermaid's tail.

Wait… HOW DID I GET A MERMAID'S TAIL?!

**Thalia's P.O.V **

Even though the events at Mako Island were completely weird, I still think we should live a normal life. In fact, I'm getting a drink from the mess hall right now.  
The lunch lady gave me one of those enchanted goblets. Now, what to drink?

"Mountain Dew," I said to the goblet. In half a second, the goblet filled with a honey colored liquid, when a thought occurred to me.  
Dad's favorite drink is Mountain Dew.

I walked over to the bronze brazier in the middle of the mess hall and knelt on one knee. I silently prayed to my dad, Please help me find out what is so dangerous about Mako Island.

I poured the soda into the fire, and the smoke turned a shade of honey. But I thought it was my imagination, because I felt a drop of soda jump onto my arm.

Then, I felt like I was melting.

About a second later, I looked down to find my legs replaced with a tail.

WHAT IN THE NAME OF ZEUS IS GOING ON?!

**Piper's P.O.V **  
I was laying down on my bunk, drenched in sweat, just waking up from a nightmare about Mako Island.

Seriously, when will they stop?

Anyways, I went to go put on my Camp Half-Blood T-shirt when I heard a voice behind me say, "Piper, hon, don't spend too much time on your looks, because you have trash duty with Mitchell. So, get to work."

I turned around to find Drew standing right behind me with her arms crossed over her chest.

And, for added cruelty, she threw a glass of water in my face. I had to report this to Chiron. So I bolted out of my cabin, and headed for the Big House.

It took me exactly 8 seconds to get there.

"Chiron, I-" was all I could manage to get out before I fell face first to the ground.

Chiron finally came out (Wonderful timing by the way), but when I caught a glimpse of his expression, I knew something was up.

"Piper," he asked, sounding in shock, "what happened to you?"

What did he mean by that?

I got my answer when I looked where my legs should have been to find them replaced with a mermaid's tail.

What is going on?


	3. Chapter 3

**Chapter 3- The Reveal  
Percy's P.O.V **

I can't believe that my girlfriend is a mermaid. Just think about it, a son of Poseidon dating a mermaid. Hopefully my dad isn't too ticked off about that.

"So," Piper said after a long silence. "Chiron, do you think that you can tell us what happened to us?"

"Well…" Chiron began, but he was cut off by Annabeth.

"Sorry, Chiron," she said, "I think I have a solution to how this happened to the three of us. Do you remember that little pool of water in the volcano we jumped into?"

"Yes," Thalia said.

"How can I forget?" Piper asked.

"Well," Annabeth began. "I think that when the full moon lined up with the mouth of the volcano that it triggered some sort of supernatural occurrence, giving us these mermaid tails."

"But there's one thing I don't get," I said. "How are they mermaids. They still can walk around."

"The tail didn't appear until Connor Stoll threw a water balloon at the back of my head." Annabeth said.

"It happened when I offered my dad some Mountain Dew." Thalia said.

"And it happened after Drew tried to get me to do trash duty and she threw a glass of water in my face." Piper said.

"It seems that the tails only appear after you come into contact with water," Chiron said. "How long did it take for the change to happen?"

"Ten seconds," they said in unison. "Why?"

"So," Chiron said. "You can't touch water for more than ten seconds."

"Wait." Thalia said. "Annabeth, you're dating a son of Poseidon. What are you going to do, treat him like acid and never talk to him again?"

"No," Annabeth said. "I'm going to make this work, mermaid tail or no mermaid tail."

She was about to walk out of the Big House when she came back around and tugged at my shirt. "You coming or what?" she asked.

I ran out of the Big House to catch up to Annabeth. "What's up?" I asked.

"I think that we can try and make this work," she said. "What do you say? Are you willing to help a mermaid out?"

I mulled it over for a minute, thinking about the possibilities of our relationship. Then I said, "I'll do anything to help you live your life. Even if you're a mermaid."

I wonder what the future has in store for us.

**Author's Notes:** I know that was short, but it was the best that I could do.


End file.
